Deputy President Thabo Mbeki and his inter-ministerial committee on Aids on Tuesday backed the department of health's controversial decision not to administer the drug azidothymidine, commonly known as AZT, to pregnant women because of cost implications.

The Caesar scientists gave a drug called lamivudine to 1,895 patients from around the world who were already taking zidovudine - also known as AZT, which is the first drug found to have a beneficial effect on HIV-positive patients, Lancet said.

Approved by the Food and Drug Administration in 1997, Combivir was the first pill to combine HIV drugs, and it contained the first ever agent approved for the treatment of AIDS - zidovudine (better known as AZT), as well as lamivudine (3TC).

While antiretroviral drugs such as AZT and Niverapine have been shown to reduce the transmission of the virus from mother to child during pregnancy and childbirth, this could be reversed if the mother breastfeeds the baby.